The project started out with exploring a rectangular in-wall speaker with a static acoustic lens. After getting that design pretty far along, the client realized that they needed to go to market with a round ceiling speaker at the same time. However, due to more varied positioning on ceilings, the lens angle on that model would need to be adjustable. That tapped into the client’s dream of making the lens “close” and be visually quiet when off and then elegantly reveal itself when on. So rather than developing two very different lens systems for each speaker, we proposed developing a single motorized lens module that could assemble into either speaker system. This would improve the consistency of the sound, look, and experience of the different models while minimizing duplicated development of the critical component.
We used a custom stepper motor to allow precise positioning and variable speed control. We included a slip clutch to prevent damage from manually over-riding the system. Isolation mounts and motor driver programming were optimized to minimize vibrations from the motor.
One of the typical problems with architectural speakers is how they transmit vibrations directly into the walls, coloring the sound. This was a particular challenge with these high powered speakers with excellent low frequency production. Many architectural speakers have an open back, using the space between studs as their acoustic chamber. That’s simply too uncontrollable. We developed sealed rear enclosures, stiffened with glass fibers and generous ribbing, that pocket into the walls to create a consistent acoustic chamber and minimize air movement in the walls. We then mechanically isolated the front housing and drivers from the rest of the enclosure with rubber and foam mounts to minimize transmission of structural vibrations.
When you have several hundred watts of power inside a sealed enclosure that’s inside an insulated wall, where does the heat go? We already knew we wanted the front housing to be very stiff for acoustic reasons. So we saw the opportunity to make that part an aluminum die-casting and use it as a heat sink as well. We then developed an aluminum sheet-metal structure to mount the electronics and transmit their heat around the drivers and to the front enclosure.